cell biology

• The vacuole is a fluid filled bag with what in it?

  water
• what happens when a cell differentiates?

  it becomes a different type of body cell.
• what kind of signals do nerve cells transmit?


  electrical
• what are the two muscle cell adaptions?

  many mitochondria, protein fibres that contract
• --- are caused whenever a foreign pathogen invades an organism

  infections
• what are two of the three ways in which an infectious disease can spread?

  air, water, direct contact
• some protist diseases are carried by what?

  vectors
• give two ways of preventing infectious spread


  vaccination, hygiene, isolation.
• vaccination can make people --- to infection

  immune
• what are the four types of pathogens?


  bacteria, viruses, protists, fungi
• what are viruses?


  they are tiny particles they invade host cells and use them to make new virus particles. once the new viruses are made the cell bursts to release the virus.
• whats bacteria?


  bacteria are small living cells that either damage cells directly or by producing toxins that damage cells and tissues. This make us feel ill.
• what are protists?


  they are single-celled eukaryotic organisms. They are often transferred to the host organism by a vector, such as an insect or mosquito.
• what are fungi?


  they are single-celled organisms that each have a body made up of thread like structures called hyphae. The hyphae are able to grow and penetrate tissues, such as human skin, causing damage
• whats the colour of iodine before its used for starch testing?

  orange - brown
• whats the colour of Benedict's solution before its used for sugar testing?

  light blue
• what the colour of ethanol solution before its used for lipid testing?

  colourless
• what's the colour of Biuret solution before it's used for protein testing?


  blue
• what colour does iodine turn when it tests positive for starch?

  blue/black
• what colour does iodine solution turn when it tests negative for starch?

  brown/ orange
• what colour does Benedict's solution turn when it tests positive for sugar?


  green - brick red
• what colour does ethanol turn when it tests positive for lipids?

  cloudy
• what colour does biuret turn when positive for protein?

  pale purple
• The mouth


  the mouth contains teeth which break food into smaller pieces and increase its surface ares to volume ratio. Carbohydrate digestion begins here. The food is shaped into a ball by the tounge and lubricated in saliva so it can be swallowed easily.
• oesphagus 


  a hollow tube with muscular walls through which food passes from the mouth to the stomach. Contractions of the smooth muscle in the wall of the oesophagus help move food towards the stomach.
• stomach


  protein digestion begins here. Glandular tissue produces enzymes and stomach acid. Muscular tissue churns food, mixing it with enzymes and acid. The acid helps to unravel proteins to enable enzyme activity, as well as lowering the ph which is optimal for stomach enzymes to work. A lower ph is detrimental to many types of microorganisms which may be present in food.
• Mitochondria 


  site of most of the reactions involved in aerobic respiration, where energy is released to fuel cellular processes.
• whats the equation for photosynthesis?


  carbon dioxide + water ----> glucose + oxygen
• what are the layers of the leaf in order?


  cuticle, the upper epidermis, the palisade layer, the lower epidermis and the stomata.